What Are Seed Oils—And Why I Ask Clients to Remove Them

Hannah Nunn
Jul 2
3 min read

The everyday food quietly fuelling inflammation and eye damage

If you’ve worked with me or taken my course, you’ll know that one of the first things I recommend is removing seed oils from your diet.

It often surprises people. Aren’t these the “healthy” oils we’ve been told to use instead of butter?

Let’s clear up the confusion—because understanding what seed oils are (and what they do inside the body) could make a big difference to your vision and overall health.

What Are Seed Oils?

Seed oils—also called industrial vegetable oils—are made from seeds that don’t naturally produce much oil. To extract it, manufacturers use high heat, chemical solvents, and industrial deodorising processes to make them shelf-stable and palatable.

These include:

Sunflower oil
Rapeseed oil (canola)
Soybean oil
Corn oil
Safflower oil
Cottonseed oil
Grapeseed oil

They’re cheap, widely used, and marketed as heart-healthy alternatives to animal fats or olive oil. But the reality is far more complex.

Why Are They a Problem for Eye Health?

Seed oils are high in omega-6 fatty acids, particularly linoleic acid. While small amounts are necessary, modern diets are overwhelmingly high in omega-6 and low in protective omega-3s.

This imbalance contributes to:

Chronic inflammation
Increased oxidative stress
Damage to mitochondria and retinal cells
Excess VEGF activity in wet AMD
Faster AMD progression

Studies show that diets high in omega-6 and low in antioxidants are associated with a significantly greater risk of AMD.

The Bigger Problem: How Seed Oils Are Made

It’s not just the omega-6 content that causes problems—it’s the way these oils are produced.

Seed oils go through extreme industrial processing, including:

High heat, which oxidises the oils before they even leave the factory
Chemical solvents like hexane, used to extract oil from hard seeds
Bleaching and deodorising, to cover the smell and taste of rancidity

This process leaves behind damaged, unstable fats and harmful by-products like aldehydes, which are toxic to cells and promote oxidative stress.

When these oils are then used in cooking—especially frying—they degrade even further, creating compounds that damage your mitochondria and cell membranes.

This matters hugely for your eyes, which are metabolically active and highly vulnerable to oxidative stress. Seed oils may be contributing to AMD in a way most people never realise.

Where Are Seed Oils Hiding?

Even if you’re not cooking with sunflower oil at home, seed oils are everywhere:

Ready meals and frozen chips
Crisps, crackers, and cereal bars
Shop-bought bread and baked goods
Margarine and “vegetable” spreads
Mayonnaise and salad dressings
Takeaways and most fried foods

They’re one of the biggest hidden drivers of inflammation in modern diets.

But Isn’t Olive Oil a Seed Oil?

No—olive oil and avocado oil come from the flesh of oily fruits, not seeds. They’re mechanically pressed, not chemically extracted, and don’t require bleaching or deodorising.

That makes extra virgin olive oil a more eye-friendly fats—rich in antioxidants and anti-inflammatory compounds.

What Can You Use Instead?

Instead of harmful seed oils, choose nourishing, more stable fats that support your eye health:

Extra virgin olive oil – for dressing and gentle cooking
Butter or ghee – stable for sautéing and baking
Coconut oil – great for higher-heat cooking
Avocado oil – for roasting or frying
Animal fats like lard or duck fat – nutrient-dense and traditional
Whole food fats – like oily fish, nuts, seeds, eggs, olives and avocados

These fats are not just “safe”—they actively support your mitochondria, reduce inflammation, and help you absorb key nutrients like lutein, zeaxanthin and vitamin A.

A Final Thought

Seed oils are one of the most common hidden inflammatory triggers I see in my AMD clients’ diets. They’re easy to swap out once you know where to look, and doing so is a powerful step toward protecting your sight.